[ronster]

If you can do your own work (and if I could do mine) I would probably be pickier about what I replace under "preventative maintenance" but I'm paying someone else to do my work and my water pump replacement was just shy of $900 over half of that was labor. Keep in mind that when you replace the pump you also have to replace coolant and bleed the system (possibly replace thermostat and serpentine belt). I've never heard of, nor read about, a water pump grenading and destroying a motor. Typically the bearing starts to go and creates a small amount of play in the beginning that creates the squeal that is the tell tale noise that tells you you need a new one. If you have plastic particles in your oil you are beyond preventative maintenance and into repair/ replace but the poster here has not indicated that is the situation only that someone (we also don't know who, friend, mechanic, guy on the street?) has indicated it should be replaced under "preventative maintenance." If you go by that you might as well replace the IMS, RMS, fuel pump, alternator, power steering pump, AC pump, MAF, AOS, secondary air system, O2 sensors and ad infinitum because they have 40K miles on them and at some point they are going to fail. I certainly wouldn't rely on the various opinions from a site to determine what is best for my car but I would rely on the opinion of a mechanic I had developed a relationship with over time that I knew had the best interest of me and my vehicle, knew my driving style and wasn't out trying to drum up business replacing parts that are still good.